Signaling system



INVENTOR 7". C RE HM Wfif y ATTORNEY July 22, 1941. T. c. REHM SIGNALING SYSTEM Filed Oct. 28, 1939- Patented July 22, 1941 UNITED STATES PATENT GFFICE 2,249,854 SIGNALING SYSTEM Theodore C. Rehm, Haledon. N. J., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a; corporation of New York Application October 28, 1939, Serial No. 301,760

6 Claims. (Cl. 179-16) trical circuit to repeat the impulses in a second electrical circuit, within the normal range of variations in the rate at which the impulses are transmitted. If the impulses are being received in the first electrical circuit at or in excess of a certain critical rate, the three aforementioned relays control the second electrical circuit to 9 transmit impulses therein of a fixed and measured duration which is the minimum allowable duration when impulses are being transmitted at the maximum normal rate. If the impulses are being received in the first electrical circuit at 'a rate lower than the critical rate, the three relays control the second electrical circuit to transmit impulses therein with an interval of fixed and measured duration between successive impulses,

the duration of this interval being the minimum allowable when impulses are being transmitted at the minimum normal rate.

Reference may be had to the patent to R. L. Stokely No. 1,861,196 of May 31, 1932; for an explanation of the necessity for measuring the impulses when the impulse rate is at or in excess of a critical rate and for measuring the intervals between impulses when the impulse rate is less than the critical rate.

A clear and complete understanding of the invention will be facilitated by reference to the impulse correcting circuit arrangement shown in the drawing, which arrangement is one embodiment 'of the invention. The invention is not limited in its application to the particular arrangement shown but is generally applicable to any impulse receiver or repeater.

Referring to the drawing,

Fig. 1 shows an impulse correcting repeater comprising an impulse receiving relay II, a fastoperate relay I3, a slow-to-release relay I4 and a slow-to-operate relay I5; and

Fig. 2 shows a modification of shown in Fig. 1.

. In each of Figs. 1 and 2, the impulse relay II the repeater is controlled by an impulse sender I0 in a first electrical circuit. Relay 2!) is an impulse relay to which the corrected impulses are transmitted in a second electrical circuit. The impulse sender I3 may be located at a subscribers station in which case the initiation of a call by the subscriber effects the connection of the calling line to an impulse receiving circuit in the central oflice in any well-known manner. Upon closure of the connection between the dial, impulse sender I0 and impulse relay I I, relay II operates closing a circuit for operating the slow-to-release relay l2. Relay I 2 prepares for the receipt of dial impulses by connecting the back contact of relay II to the winding of relay I3 and by closing a circuit including the lower winding of coil I8 and back contacts of relays I4 and I6, for operating relay 2!). When the dial I9 is operated, it alternately opens and recloses the impulse circuit one or more times depending upon the digit dialed. Relay II releases and reoperates in response to each impulse thus transmitted by the dial I9. Being slow in releasing, relay I2 remains operated during the response of relay II to dial impulses. The release of relay II in response to the first impulse of a series closes the circuit for operating relay I3. Relay I3 is fast in operating andthe opening of the impulse circuit may be as short as the operating time of relay I3. The resistor I9, which is connected in parallel with the winding of relay I3 does not substantially effect the operating time of relay I3 but increases its releasing time. Relay I3 locks under control of relay I5, closes a circuit for operating relay I4, and closes a circuit for operating relay I5. Relay I4 is a slow-to-release relay which remains operated, while all the impulses in the series are being received and repeated, unless the impulses are being received at a rate lower than a critical rate. We will first assume that the impulses are being received at the critical rate or a faster rate and that relay I4 remains operated until all of the impulses in the series have been repeated. The operation of relay I3 closes a circuit for holding relay 2E] operated after relay I4 operates. Relay I4 closes a circuit for operating relay l6 and, being slow in releasing, relay I6 remains operated until all of the impulses in the series have been received and repeated. With relay I6 operated, the circuit for repeating impulses to relay 20 excludes the lower winding of coil I8 thereby insuring the reoperation of relay 2!] between impulses. The circuit for energizing relay 20 remains closed after relay l3 operates until relay I3 releases. When relay I5 operates, it locks under the control of relay ll if relay II has not reoperated. The operation of relay l causes the release of relay l3 and the release of relay l3 opens the outgoing impulse circuit to cause the release of relay 20. The release of relay l3 also opens the operating circuit of relay it but being slow in releasing and the rate'of impulse transmission being at or above the critical rate relay I l remains operated. When relay l3 releases, relay l5 releases unless relay H has not reoperated in which case relay i5 remains operated until relay ll reoperates, When relay ll releases in response to the second impulse of a series, relay l3 reoperates thereby closing the outgoing impulse circuit to reoperate relay 2%. 'Relay l3 again closes the circuits for energizing relays l4 and operates, relay I3 again releases, opening the outgoing impulse circuit to release relay 20. release of relay l3 and reoperation of relay atthe' end of thesecond impulse causes the release of relay Hi. This cycle of operations is repeated for each succeeding impulse received by relay H.- When relay l3 releases after the last impulse of the series has been received, relay l4 releases to close the Outgoing loop and reoperate relay 28. Thus the last impulse of each series transmitted to relay 213 is measured by the release of relay M and the interval during which the outgoing impulse circuit is closed between impulses is'measured by just two relays, that is, the operating time of relay l5 plusthe release time of relay l3. Relay !5 is so designed that its operate time issuch as to make certain that the outgoing impulse circuit is closed and remains closed for the minimum allowable interval between impulses when the impulses are being repeated at or in excess of the critical rate.

If now the rate at which impulses are being received by relay l I is less than the critical rate, relayl4 releases after relays l3 and i5 have responded to an impulse, because the operation of relay 13 in response to a second impulse does not occur within the release time of relay M. The release of relay l lcloses the-outgoing impulse circuit' to reoperate relay 2%). When relay ll releases in response to the second impulse, relay [3 reoperates and again closesthe circuits for operating relays l4 and I5. The outgoing impulse circuit is again opened when relay l3 releases and reclosed when relay I4 releases. Thus, when the impulse rate is lower than the critical rate, it is the opening of the outgoing impulse circuit which has a fixed duration and which is measured by the release time of relay I4. When relay l4 releases at the end of a train of impulses, the release of relay l6 reinserts the lower winding of coil 18 in the outgoing-circuit; When relay l l releases due to release of the connection by the calling subscriber, an impulse is transmitted in the outgoing impulse circuit to relay 26, the impulse being ended by the release of relay it. When relay [2 releases, the outgoing impulse circuit is opened to cause release of relay-20 as a disconnect'signal.

V In some cases it is desirable thatthe sending of an impulse, when the calling subscriber releases the connection, be prevented to avoid the possibility of false operation; or it may be desirable to secure a faster release of the impulse correcting circuit and succeeding circuits involved in a connection. The repeater shown in Fig. 2 is similar to Fig. 1 except that relay I1 is added to prevent the sending of a falseimpulse to relay Zilwhenrelayl l releases-due to release of the The l5. When relay l5 connection. The winding of relay I! is connected in the locking circuit of relay l5 so that,

when relay l3 releases, relay ll operates and relay I5 is held through the back contact of relay Relay ll holds the outgoing impulse circuit open so that relay 20 does not reoperate after its release due to the release of relay l3.

While the outgoing impulse circuit is shown as being a loop impulse circuit and one in which the impulses consist of openings of the circuit, it is obvious that the outgoing impulse circuit may be any type of circuit, for instance, single wire, simplex, phantom, etc., that the impulses may consist either of openings or closures of the circult, and that the circuit may be either an alternating-current or a direct-current circuit.

What is claimed is:

1. In combination, a first circuit including an impulse sender and an impulse receiving relay, 2. second circuit, and means for repeating in said second circuit a train of impulses received by said relay, said means comprising a single, slowto-release relay for measuring and fixing the duration of the impulses transmitted in said second circuit when and if the impulse rate is lower than'a critical'rate, and comprising only two relays, one a fast-operating relay and the other a slow-operating relay, for measuring and fixing the interval between succeeding impulses transmitted in said second circuit when and if the impulse rate is equal to or in excess of said critical rate.-

2, In combination, an incoming impulse circuit, an impulse receiving relay in said circuit for responding to impulses; a fast-operating relay, a slow-operating relay, a slow-releasing relay, a circuit closed by the release of the impulse relay for operating said fast-operating relay, said circuit including a back contact of the slowoperating relay, a circuit closed by the operation of the fast-operating relayfor operating the slow-operating relay, a circuit closed by the operation'of the fast-operating relay for operating the slow-releasing relay, circuits for holding said slow-operating relay operated until the impulse relay reoperates and the fast-operating relay releases, an outgoing impulse circuit, contacts on said fast-operating relay for opening the outgoing impulse circuit'in response to each release of said impulse relay, and contacts on said slow releasing relay for closing the outgoing impulse circuit a predetermined interval of time after the opening of this circuit by the release of the fastoperating relay, said contacts of the fast-operating relay being effective to close the outgoing impulse circuit incase said iasteoperating relay is reoperated due to the response of the impulse relay to a second impulse prior to the release of said slow-releasing relay.

3. An impulse repeater'comprising an impulse relay, a fast-operate relay, a slow-operate relay and a slow-release relay, a circuit closed by said impulse'relay at the beginning of each incoming impulse for operating said'fast-operate relay,

operate relay in parallel with a back contact of said slow-release relay.

4. In an impulse repeater according to claim 3, a relay having a contact in said outgoing impulse circuit, the Winding of said relay being connected in series with the winding and a locking contact of said slow-operate relay to prevent reclosure of the outgoing impulse circuit when said impulse relay releases and does not reoperate prior to the release of said slow-release relay.

5. In combination, a first circuit including an impulse sender and an impulse receiving relay, a second circuit, and means for repeating in said second circuit a train of impulses received by said relay, said means comprising a single, slow-torelease relay for measuring and fixing the duration of the impulses transmitted in said second circuit When and if the impulse rate is lower than a critical rate, and comprising only two relays, one a fast-operating relay and the other a 510W- operating relay, for measuring and fixingthe interval between succeeding impulses transmitted in said second circuit when and if the impulse rate is equal to or in excess of said critical rate,

each of said fast-operating, slow-to-release, and slow-operating relays comprising a single winding.

6. An impulse repeater comprising an impulse relay, a fast-operate relay, a slow-operate relay and a slow-release relay, each of said fastoperate, slow-operate and slow-release relays comprising a single Winding, a circuit closed by said impulse relay at the beginning of each incoming impulse for operating said fast-operate relay, a circuit closed by the operation of said fast-operate relay for operatively energizing said slow-operate relay, the operation of said slowoperate relay effecting the release of said fastoperate relay, a circuit for holding said slowoperate relay until the end of each incoming impulse, a circuit closed by each operation of said fast-operate relay for operatively energizing said slow-release relay, and an outgoing impulse circuit controlled by a front contact of said fastoperate relay in parallel with a back contact of said slow-release relay,

THEODORE C. REI-DM. 

